Matchless 1964 G12 650, Instruction Book, Page: 7 / 104

Ignition
(Magneto)—
Twins
Make
Lucas
Type
K2F
Rotation
Anti-clock
Point gap
·012 in.
Sparking Plug
Model
Std.
CSR model
Hake
K.L.G.
K.L.G.
Type
FE80
FE220
Thread
14 mm.
14 mm.
Reach
¾ in.
¾ in.
Point gap
·020 to ·022 in.
·020 to ·022 in.
Connecting rod—Twins
Internal diameter small end
¾ in. + ·0005 in. (H)
¾ in. – ·0000 in. (L)
Gudgeon pin diameter
¾ in. – ·0001 to – ·0003 in.
NOTE—The 650 c.c. con rods use chamfered end caps. Early type rods will not interchange.
Crankshaft diameters
Crankpin
H—1·62575 in.
L—1·62525 in.
Centre bearing
H—1·62675 in.
L—1·62625 in.
Pistons (
standard size). Top skirt diameter
(Twins)
650 c.c.
H—2·8295 in.
L—2·8287 in.
Pistons (standard size). Top skirt diameter
(Singles)
350 c.c.
2·9071 in.
+ or – ·0005 in.
500 c.c.
3·2437 in.
+ or – ·0005 in.
Piston rings
Normal gap ·006 in. maximum permissible ·030 in.
Engine shaft location—Singles
If the flywheel driving side shaft is removed it must be correctly located otherwise the efficiency of the
alternator will be impaired.
On the face of the driving side flywheel is a mark In the form of a " d o t " . The key for the rotor must
line up with this marking, for correct location.
Valve guide projection
(top of guide to boss)—
Singles
Inlet—½ in. Exhaust—½ in.
Valve timing pinion—Singles
Retained by nut, threaded
v
in. by 26 threads per in. Left hand thread. Part number 000221.
Valve springs—Singles
Free length (between centre of wire)— 2 in.
Renew when
x
to ¼ in. less than normal free length.
Valve springs—Twins
Outer valve spring
Free length Part number
2 33/64 in. 018348
Inner valve spring
Free length Part number
2
Q
in. 018347
Renew valve springs when
x
to ¼ in. less than normal free length.
The following are the only "oversize" variations provided for the 350 and 500 c.c. Single Cylinder machines
Big-end rollers: Cylinder re-bore: Pistons and rings:
·001 in. oversize ·020 in. and ·040 in. oversize ·020 in. and ·040 in. oversize
Oversize parts—Singles
Oversize or undersize parts—Twins
The following are the only "oversize" variations provided for the Vertical Twin machines.
Big-end and crankshaft centre main bearings:
Undersize
·010 below normal. (Journals to be re-ground to suit)
·020
·030
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Cylinder re-bore: n o t s i P s and rings:
·020 in. and ·040 in. oversize ·020 in. and ·040 in. oversize
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